Rock scaling in a mine is an operation that consists in the probing, with a steel bar, of the walls of a gallery in a subterranean mine, the goal being to locate and remove unstable rocks, a possible cause of accidents. Nowadays, this operation is done manually and is, in itself, dangerous. The maneuvering of such a steel bar requires a lot of energy (the bar weighs around 11 lbs) which increases the risks of injuries due to mishandling of the bar, due to using an improper bar and proceeding to an incomplete scaling operation.
U.S. Pat. No. 5,180,210 Lister, Jan. 19, 1993, shows a tool having at one end a chisel 64 (FIG. 1) provided with a part 65 aligned and connected to a piston to reciprocate with the piston in response to high pressure air delivered to the cylinder. The chisel has a cutting edge which is offset from the axis of the piston to facilitate the chiseling of obstructions inside a chimney. The tool is created to provide a cutting action without any lever effect. If it were so the chisel, having a wedging sharp edge in place of a cutting edge, could damage the interior of the chimney.
U.S. Pat. No. 4,871,214 Pradelle, Oct. 03, 1989, illustrates a device for removing boulders loosened by an explosion from the hanging roof of a mining gallery. The tool works by vibrating the rocks with an especially designed head 11 (FIG. 2) the head having the shape of a torus. With this method, rock will slacken until it eventually falls. The tool has no levering capability.
U.S. Pat. No. 3,619,009 O'Leary, Nov. 09, 1971, shows the tip 13, bent in an "L" shape, of another type of scaling tool. The curve facilitates the work of the operator during the penetrating action of the tip of the tool into cracks in the rock. However, the lever effect is due to human effort, the operator having to push on the handle of the tool perpendicularly against the rock and lift the tool by moving the tool parallel to the surface of the rock to remove the stones. Moreover the tip does not have a shape facilitating the penetrating and wedging action of the its point.